The two faces of HIV/AIDS in the brain

According to “Diagnostic Imaging” Anne Osborn is among the 20 most influential people in radiology. In 1988 she was elected the first female president of the American Society of Neuroradiology (ASNR). Osborn is the author of more than 20 books, among them the highly influential textbook “Diagnostic Neuroradiology”.

Osborn chose the topic “The two faces of HIV/AIDS in the brain: The face you know – and the one you don’t” at ECR because of the location of the congress and its exemplary history of assisting radiologists in other continents. “ECR has, since its inception, established a tradition of educational outreach to people in developing countries, which I think is very admirable. ECR is uniquely positioned as the centre point between Western and Eastern Europe, between Europe and Africa, and Europe and Asia. There are a lot of radiologists from less-developed countries who attend ECR and who might not be able to attend meetings like RSNA because of the travel expense.”

She took the opportunity to appeal to ESR members to support worldwide efforts to advance HIV/AIDS treatment. “We can support educational outreach, making generic drugs available and work together to eradicate co-morbid diseases like TB and malaria, which together kill more people annually then HIV itself does.”

HIV/AIDS is a public health concern with about 40 million cases worldwide – 95 % of them are found in relatively low income countries. HIV is a retrovirus entering the brain within 2 hours and 2 days. “The damage is most severe in the parts of the brain that are responsible for movement, memory or planning. Therefore, the patient who develops HIV in the brain often has severe cognitive impairment”, Osborn explained. But its manifestations in the central nervous system can be quite different depending on the environment in which it presents. These differences, which are particularly striking between rich and poor countries, should be recognised and addressed by all, as local problems are likely to spread in the near future, said Professor Osborn.

Osborn chose famous basketball player Earvin “Magic” Johnson who has been HIV positive for almost 20 years as an example for “active and healthy” HIV/AIDS patients in the European or American resource. ”The face of HIV/AIDS has undergone an interesting transition in these countries. In the past decade survival has increased from about 10 ½ years to 22 ½ years. Over this period of time HIV/AIDS has become from a ‘death sentence’ to a chronic disease. That means, what we see in the brains of long term survivors mostly ‘opportunistic’ infections like toxoplasmosis, progressive multifocal leukoencephalopathy (PML), immune reconstitution inflammatory syndrome (IRIS), or brain tumours, which all occur in result of long term highly active antiretroviral therapy (HAART).”

The CD4 (cluster of differentiation 4) count which is the measure of the affective lymphocytes count is very much related to the type of brain disease these patients develop. “If you have a CD 4 count of over 500, these patients are in good shape. As the CD 4 count gets worse, the number of infections such as tuberculosis (TB) or AIDS dementia all increase. When the patient has a CD 4 count under a hundred, he is subjected to a number of these diseases.”
For example toxoplasmosis is an opportunistic infection which causes lesions in the deep gray matter of the brain. “The question, if a lesion is tumour or infection makes a big difference because the treatment is going to be different”, explained Osborn. On the other hand, lymphoma – cancer caused by the own immune system – is going to be the most common cancer in the future, Osborn prognoses. ”Lymphoma has a different appearance in AIDS-related patients (AIDS NHL).

The other face of AIDS appears when there is no access to antiretroviral therapy. In that situation, when the environment changes, the nature of the disease changes as well. Instead of a chronic but manageable disease, HIV/AIDS presents as an acute, fulminating, often lethal disease in resource-poor nations.

According to the WHO, “AIDS is out of control” in Africa, many parts of India and some parts of China. The most dramatic manifestation is what Osborn referred to as “the deadly intersection” between HIV/AIDS and drug-resistant tuberculosis/ “Killer” (TB), a disease on the rise in many poor countries.

“If a patient is co-infected with both HIV/AIDS and TB, which often happens in areas such as sub-Saharan Africa, each disease magnifies and greatly amplifies the infectiousness and lethality of the other – with devastating consequences. It is this combination of HIV/AIDS and TB that forms a truly deadly intersection,” explained Osborn.

In Africa and many parts of Asia, HIV/AIDS and TB are rampant, and access to appropriate treatments is limited. This means radiologists see acute manifestations such as bacterial brain infections and acute fulminating meningitis which are very rare in developed countries. “These patients simply don’t survive long enough to develop more familiar consequences of chronic HIV/AIDS such as opportunistic infections, tumours, and recently-described entities such as immune reconstitution inflammatory syndrome (IRIS),” Osborn pointed out.

However, radiologists in America and Europe will increasingly see such cases in the future as migration increases and the prevalence of multi-resistant and extreme drug-resistant TB rises, even in rich countries. Radiologists must be prepared to meet and recognise a face of HIV/AIDS that they have never seen before.

“We need to become familiar with unusual manifestations of HIV/AIDS. We need to learn now how to recognise these signs, this new unfamiliar ‘face’ of HIV/AIDS that we don't know yet, because these cases will probably be showing up in our practises very soon,” Osborn urged.

06.03.2010

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